Valve

ABSTRACT

A valve comprises a valve mechanism located within a housing arrangement, wherein the housing arrangement comprises an outer housing configured to be mechanically secured with a fluid conduit system, and an inner housing located within the outer housing and configured to contain pressure.

FIELD OF THE INVENTION

The present invention relates to a valve, and in particular, but notexclusively, to a valve for use in a landing string arrangement, forexample for use within a subsea test tree.

BACKGROUND TO THE INVENTION

Landing strings are used in the oil and gas industry for through-riserdeployment of equipment, such as completion architecture, well testingequipment, intervention tooling and the like into a subsea well from asurface vessel. When in a deployed configuration the landing stringextends between the surface vessel and the wellhead, for example awellhead Blow Out Preventor (BOP). While deployed the landing stringprovides many functions, including permitting the safe deployment ofwireline or coiled tubing equipment through the landing string and intothe well, providing the necessary primary well control barriers andpermitting emergency disconnect while isolating both the well andlanding string.

Wireline or coiled tubing deployment may be facilitated via a lubricatorvalve which is located proximate the surface vessel, for example below arig floor.

Well control and isolation in the event of an emergency disconnect isprovided by a suite of valves which are located at a lower end of thelanding string, normally positioned inside the central bore of the BOP.The BOP therefore restricts the maximum size of such valves. The valvesuite includes a lower valve assembly called the subsea test tree (SSTT)which provides a safety barrier to contain well pressure, and an uppervalve assembly called the retainer valve which isolates the landingstring contents and can be used to vent trapped pressure from betweenthe retainer valve and SSTT. A shear sub component extends between theretainer valve and SSTT which is capable of being sheared by the BOP ifrequired.

As noted above, the landing string may accommodate wireline and/orcoiled tubing deployed tools. In this respect the various valveassemblies, such as in the SSTT, must define sufficiently large internaldiameters to permit unrestricted passage therethrough. However, thevalve assemblies also have outer diameter limitations, for example asthey must be locatable within the wellhead BOP. Such conflicting designrequirements may create difficulty in, for example, achievingappropriate valve sealing, running desired tooling through the valvesand the like.

Furthermore, the landing string must be capable of cutting any wirelineor coiled tubing which extends therethrough in the event of an emergencydisconnect. It is known in the art to use one or more of the valves toshear through the wireline or coiled tubing upon closure. However,providing a valve with the necessary cutting capacity may be difficultto achieve within the geometric design constraints associated with thelanding string. For example, the valve actuators must be of sufficientsize to provide the necessary closing/cutting forces, which may bedifficult to accommodate within the restricted available size.

The landing string must also be designed to accommodate the significantin-service loadings, such as the global tension from a supported lowerstring (e.g., a test string, completion or the like), bending loads,valve actuation loading, internal and external pressures and the like.As the industry continues to move into fields with increasing formationand water depths, the resulting structural demands on the landing stringalso become more extreme. For example, landing string global tensionrequirements far in excess of 4.5 MN (1,000,000 lbf) and wellborepressures which can exceed 690 bar (10,000 psi) are typical. Suchloadings must be accommodated across regions including the various valveassemblies, such as the SSTT. It is therefore necessary to design thevalve housings and appropriate end connections to be capable ofaccommodating the global applied tension, bending loads, valve actuationloading and pressures. This results in the use of thick walled valvehousings, which can compromise the achievable valve internal diametersand sealing integrity. Furthermore, current industry standards call forall connections through such landing string valve assemblies to beconfigured to avoid separation during use to improve fatigueperformance. Such connections may include bolted connections of thevalve housings into the landing string. This typically requiressignificant upsizing of the connections and establishes furtherdifficulties in achieving sufficiently large internal diameters withinthe outer diameter constraints, such as dictated by the BOP.

Issues such as those described above are not unique to valves withinlanding string applications. For example, there is a general desire inthe art to minimise the size of valves, for example to provide minimalvalve housing dimensions while still maximising the inner diameter toaccommodate appropriate valve mechanisms and the like.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided avalve comprising a valve mechanism located within a housing arrangement,wherein the housing arrangement comprises an outer housing configured tobe mechanically secured with a fluid conduit system, and an innerhousing located within the outer housing and configured to containpressure.

In use, the outer housing may permit the valve to be secured with afluid conduit system while the inner housing provides an appropriatepressure barrier for pressure internally and/or externally of thevalve/fluid conduit system, wherein the valve mechanism permits controlof flow along the fluid conduit system.

The outer housing may be configured to be secured in-line with a fluidconduit system.

The valve may be configured to form part of a fluid conduit system.

The fluid conduit system may be defined by one or more tubingcomponents, flow equipment such as other valves, flow meters, shear-subcomponents or the like.

The valve may have numerous applications as might readily be understoodby those of skill in the art. In some embodiments the valve may beconfigured for use within a landing string assembly. For example, thevalve may define or form part of a Subsea Test Tree (SSTT), a retainervalve, a lubricator valve or the like. In such an arrangement a landingstring may define a fluid conduit system.

The outer housing may be defined as a structural housing. That is, theouter housing may be provided primarily to accommodate mechanicalforces, such as axial and bending forces, associated with the fluidconduit system while providing minimal or no pressure containment, forexample of internal and/or external pressures. The inner housing may bedefined as a pressure housing. That is, the inner housing may beprovided primarily for pressure containment, for example of internaland/or external pressures, while providing minimal or no contribution toaccommodating mechanical loading associated with the fluid conduitsystem This arrangement may permit each individual housing to bedesigned and/or selected to meet more focussed or specific operationalrequirements.

These divided roles of the outer and inner housings may provide a numberof advantages, such as reduction in wall thickness, weight, costs andthe like. In particular, the provision of an outer structural housingand a separate pressure containing inner housing may permit a reductionin the global housing wall thickness to be achieved. That is, as theouter housing is not intended to be pressure containing, the wallthickness of this can be significantly reduced. Furthermore, as theinner housing is intended for pressure containment, and not, forexample, to accommodate significant tensile and bending loads, this toocan have a minimal wall thickness for its limited function. As such, thecombined wall thickness can be reduced relative to a single structurewhich is designed to be exposed to both mechanical and pressure loading.

Reducing the overall wall thickness of the housing may permit a largerhousing inner diameter to be available. This may provide a number ofadvantages, such as assisting to maximise the viable size of the valvemechanism, permitting larger equipment to be deployed through the valve,valve sealing area and the like. Furthermore, such dimensionaladvantages may be achieved without increasing, or without significantlyincreasing material usage. For example, being able to provide a thinnerglobal wall thickness across separate outer and inner housings relativeto a single housing design may permit an increased inner diameter to beachieved without also requiring an increased outer diameter. This mayhave advantage in applications in which the valve must be located withinan outer constraining structure, such as a pipeline, borehole, casingstring, wellbore, riser, BOP or the like.

By the outer housing being mechanically secured, for example in-line,with a fluid conduit system mechanical forces, such as tensile forcesand bending forces, may be transmitted across the outer housing. Suchmechanical forces may originate from the fluid conduit system, such asfrom the weight of the fluid conduit system or the like.

The outer housing may comprise a connection arrangement for permittingmechanical connection with a fluid conduit system. The connectionarrangement may comprise first and second connectors for securing with afluid conduit system, for example in-line with a fluid conduit system.The first and second connectors may be configured to be secured tosimilar components, such as tubing, for example. The first and secondconnectors may be configured to be secured to different components. Forexample, one connector may be configured to be secured to tubing, andone connector may be configured to be secured to flow equipment such asanother valve, flow meter, tubing hanger, choke, manifold, or the like.

At least one of the first and second connectors may comprise a flangeconnector.

At least one of the first and second connectors may define a preloadedconnector. Such preloading may be achieved by use of one or morepreloaded bolt connections, clamp assemblies or the like. Suchpreloading may permit the point of connection from separating duringuse, for example due to axial and bending forces. As the inner housingis located internally within the outer housing and does not include anydirect mechanical connection with the fluid conduit system, anyrequirement to provide such a preloaded connector with the inner housingis eliminated. That is, only the connection between the outer housingand the fluid conduit system may require preloading, for example to meetrequired or preferred industry standards.

The inner housing may be axially contained within the outer housing. Insuch an arrangement any axial loading experienced by the inner housing,for example due to internal pressures, valve actuation forces and thelike may be transferred to the outer housing. The inner housing may beaxially contained between first and second connectors of the outerhousing. At least a portion of the valve mechanism may be axiallylocated, for example secured, between the outer and inner housings. Forexample, at least a portion of the valve mechanism may be securedbetween one of the first and second connectors and the inner housing,for example an axial end face of the inner housing.

The outer housing may comprise an axially extending wall sectionconfigured to encapsulate the inner housing. As pressure forces arecontained primarily by the inner housing, the wall thickness of theaxially extending wall section of the outer housing may be minimised.

The outer housing may define a barrel-type housing.

The outer housing may be split to permit access to install, remove,replace, inspect or the like the inner housing and/or the valvemechanism. In one embodiment the outer housing may be longitudinallysplit, that is, split along its length. The outer housing may compriseat least two housing segments. The housing segments may be hingedlyconnected together. The housing segments may be configured to be securedtogether when in a closed configuration. For example, the housingsegments may be secured together in a closed configuration when theouter housing is secured to a fluid conduit system, for example viafirst and second connectors. The housing segments may be secured along alength of separation, for example along the length of the split definedbetween the different segments. This arrangement may provide orestablish appropriate hoop stiffness within the outer housing which maybe required to resist bending forces, for example.

The housing segments may be secured together by a bolting arrangement.The bolting arrangement may be provided along one or more sides orregions of separation between different segments.

The housing segments may be secured together via one or more tangentialbolts.

Adjacent housing segments may comprise one or more connecting portionsextending at least partially along the length of split defined betweenthe adjacent segments, wherein opposing connecting portions of eachsegment may be secured together, for example via bolting. A plurality ofconnecting portions may be provided on each adjacent segment. Axiallyadjacent connecting portions on a single segment may be separated by aslotted region, such as a laterally extending slot. Such separationbetween axially adjacent connecting portions may permit appropriateredirection of stress, for example due to tensile loading, around andacross this area of connection between segments.

The housing segments may be secured together via one or more axiallyextending connecting members, such as a connecting rod, bolt or thelike. In such an arrangement adjacent housing segments may compriseinterleaving portions which are held together via such an axiallyextending connecting member.

As the outer housing is not intended to be pressure containing anysealing, or at least any significant sealing arrangements, may not berequired between individual housing segments when secured together.However, in some embodiments a sealing arrangement may be providedbetween different segments of the outer housing. In other embodiments nosealing arrangement between different segments may be provided. This maypermit equalisation of pressure internally and externally of the outerhousing, thus assisting to eliminate or minimise any stress, for examplehoop stress, applied via effects of pressure.

At least a portion of the outer housing may define a generallycylindrical outer profile.

At least a portion of the outer housing may define a generallynon-cylindrical outer profile having different dimensions in mutuallyperpendicular lateral directions. For example, at least a portion of theouter housing may define a generally oval outer profile, ellipticalouter profile or the like. Such an arrangement may permit umbilicals orthe like to be accommodated between the valve housing and an outerconstraining structure, such as an outer pipeline, borehole, casingsection, riser, BOP or the like.

In some embodiments a connection arrangement, such as a flangeconnection arrangement of the outer housing may define a non-cylindricalprofile.

At least a portion of the outer housing may define a generallycylindrical inner profile.

The outer housing may define one or more axial holes, such as gundrilled holes, which may accommodate fluid communication, for exampleacross the entire length of the housing, to provide hydraulic power tothe valve mechanism or the like.

The inner housing may define a generally cylindrical profile.

The inner housing may be isolated from mechanical connection with afluid conduit system. For example, the inner housing not be exposed, ormay be exposed to a far lower proportion of mechanical loadingassociated with the fluid conduit system as the outer housing. This lackof connection thus eliminates any requirement for a preloaded connectionwith the fluid conduit system, for example as may be required orpreferred by industry standards. This permits space saving to beachieved, for example in terms of available internal diameter thusallowing a larger valve mechanism to be utilised.

The inner housing may be defined by a pressure containing sleeve.

At least a portion of the valve mechanism may define part of the innerhousing.

Any suitable valve mechanism as would readily be selected by a person ofskill in the art may be utilised. Such valve mechanisms may comprise,for example, a ball valve, butterfly valve, poppet valve, needle valve,check valve, choke valve, gate valve, piston valve or the like. Thevalve mechanism may generally comprise a valve seat and a valve memberconfigured to cooperate with the valve seat to provide flow control.

The valve mechanism may comprise an actuator, for example an actuator todisplace a valve body. The actuator may comprise a hydraulic actuator,electrical actuator, mechanical actuator, thermal actuator, pressuredifferential actuator or the like. The actuator may comprise a pistonarrangement.

The valve mechanism may be configured to cut a body extending at leastpartially through the valve. This arrangement may permit full closure ofthe valve mechanism to be achieved without impedance from the body.Further, such cutting may be provided not only where full closure isrequired. For example, the valve mechanism may be utilised to cut a bodyand then return to an open configuration thereafter.

The valve mechanism may be configured to cut an elongate body, such astubing, coiled tubing, wireline, slickline, a tool string or the like.

The ability to maximise the inner diameter of the housing by use ofseparate housing components may permit the valve mechanism to beappropriately configured, for example in terms of size, availablecutting force and the like, to cut through a body.

In one embodiment the valve mechanism may comprise a ball valvemechanism which includes a ball seat and a ball member, wherein the ballmember is rotatable relative to the ball seat to provide flow control.

The ball seat may be axially contained between the inner housing, forexample an axial end of the inner housing, and the outer housing, forexample a connecting portion of the outer housing. Such an arrangementmay provide a simple modular construction, permitting ease of assemblywhile ensuring sufficient retention of the ball seat within the ballvalve. Furthermore, such an arrangement may eliminate the requirement toprovide a mechanical connection of the ball seat within the ball valve,providing advantages in terms of, for example, space saving.

The ball seat and ball member may define respective through bores eachhaving a bore edge.

The respective through bores of the ball seat and ball member may definea flow path through the valve. The ball member may be rotated relativeto the ball seat to misalign the respective through bores to prevent orrestrict flow through the valve, and may be rotated relative to the ballseat to align, for example coaxially align, the respective through boresto permit or increase flow through the valve.

The bore edge of at least one of the ball seat and ball member may beconfigured to cut a body extending at least partially through the valveupon closure of the ball member.

The bore edge of at least one of the ball seat and ball member maydefine a recessed cutting region for cutting a body.

Both the ball seat and ball member may define a recessed cutting region.In such an arrangement the respective recessed cutting regions may beconfigured similarly, or differently. Respective recessed cuttingregions of the ball seat and ball member may be generally aligned witheach other. Such alignment may be considered to exist in a plane whichis perpendicular to a rotational axis of the ball member. In otherembodiments the respective recessed cutting regions of the ball seat andball member may be misaligned.

Only one of the ball seat and ball member may define a recessed cuttingregion. This arrangement may be advantageous in that the component whichdoes not comprise a cutting recess may hold the body being cut in a morecentral position relative to the ball seat and ball member, presentingthe body in a better position to be cut. In one embodiment only the ballmember may define a recessed cutting region.

A recessed cutting region may be recessed relative to an associatedthrough bore. That is, the recessed cutting region may be outwardlyrecessed relative to an associate through bore.

A recessed cutting region may be configured to at least partiallyreceive a body to be cut. The recessed cutting region may be configuredto entirely receive a body to be cut. In some embodiments, large bodies,for example large diameter bodies may only partially be received withinthe recessed cutting region.

A recessed cutting region may be provided in a leading edge of one orboth of the ball seat and ball member. In this respect the leading edgesof the ball seat and ball member may be considered to be those edges ofthe respective through bores which initially pass each other uponclosure of the ball member relative to the seat.

Upon closure of the ball member the bore edge of the ball member throughbore may engage and displace a body which at least partially extendsthrough the valve until said body is engaged between the ball memberbore edge and the ball seat bore edge and at least partially receivedwithin a recessed cutting region, such that further rotational movementof the ball member towards a closed position permits cutting of thebody, typically by a shearing action, by the recessed cutting region.

A recessed cutting region may define a cutting edge. The cutting edgemay be formed continuously with the edge of an associated through boreedge.

A recessed cutting region may define at least two cutting edgesconfigured to permit simultaneous cutting into separate regions of abody, for example upon initial contact with the body. A recessed cuttingregion may be arranged to define at least two points of cutting contactwith a body during cutting thereof. During initial contact with the bodyduring cutting thereof the at least two points of cutting contact may beoffset from a central region of the body. During initial contact withthe body the at least two points of cutting contact may be offset from acentral region of the recessed cutting region. This arrangement maypermit the force of cutting to be divided between the different pointsof cutting contact, assisting to prevent adverse compression, collapsingor the like of the body. Furthermore, this arrangement may prevent largecutting forces being applied initially centrally of a body which mayassist to prevent collapse of the body, for example. Also, thisarrangement may require less torque through the ball member to cut thebody. Such reduced loading is anticipated to reduce damage to thecomponents of the ball valve which may assist in preventing or reducingany damage to sealing regions. During cutting of a body, the at leasttwo points of cutting contact with the body may converge together. Thatis, the at least two points of cutting contact may propagate relative tothe body until converged together.

The at least two cutting edges may be defined by two distinct cuttingedges. In some embodiments the at least two cutting edges may be definedby separate regions of a single cutting edge.

The at least two cutting edges may be aligned substantially obliquelyrelative to a rotation axis of the ball member.

At least one cutting edge may be generally straight. At least onecutting edge may be curved, for example arcuate.

A recessed cutting region may be defined by a notch extending into theedge region of an associated through bore.

A recessed cutting region may be generally v-shaped, for example definedby a v-shaped notch.

A recessed cutting region may be arcuate, for example.

The bore edge of at least one of the valve seat and ball member maydefine a single recessed cutting region. The bore edge of at least oneof the valve seat and ball member may define at least two recessedcutting regions. In such an arrangement at least two cutting regions maybe separated from each other. At least two cutting regions may merge oroverlap each other.

A recessed cutting region may comprise a projection, for example acentral projection, which may function to pierce the body, for examplecentrally of the body.

A recessed cutting region may comprise a serrated edge.

The ball valve may comprise one or more inserts located within arecessed cutting region. The insert may define a cutting edge. Such aninsert may facilitate easier maintenance and the like. For example, tore-establish a sufficient cutting edge only the insert need be replaced,rather than the entire ball.

The ball member may define a sealing area which cooperates with anappropriate sealing area of the ball seat, at least when the valve is ina closed configuration. The ball seal area is rotationally offset fromthe ball through bore. The recessed cutting region may be defined withinthe ball member, wherein said cutting region is recessed towards thesealing area.

According to a second aspect of the present invention there is provideda method of controlling flow along a fluid conduit system, comprising:

securing a valve housing arrangement to a fluid conduit system, whereinthe valve housing arrangement includes an outer housing which providesmechanical connection to the fluid conduit system and an inner housinglocated within the outer housing and which contains pressure; and

controlling flow along the fluid conduit using a valve mechanism locatedwithin the valve housing.

According to a third aspect of the present invention there is provided asub sea test tree comprising:

-   -   a housing arrangement; and    -   a valve mechanism located within a housing arrangement,    -   wherein the housing arrangement comprises an outer housing        configured to be mechanically secured with a fluid conduit        system, and an inner housing located within the outer housing        and configured to contain pressure.

The housing arrangement may be configured to be located within a BlowOut Preventor (BOP).

According to a fourth aspect of the present invention there is provideda landing string assembly comprising a valve, wherein the valvecomprises:

-   -   a housing arrangement; and    -   a valve mechanism located within a housing arrangement,    -   wherein the housing arrangement comprises an outer housing        configured to be mechanically secured with a landing string        fluid conduit system, and an inner housing located within the        outer housing and configured to contain pressure.

The valve may define a sub sea test tree.

The outer housing may be mechanically secured in-line with a fluidconduit system.

Features defined in relation to one aspect defined above may beassociated with any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described,by way of example only, with reference to the accompanying drawings, inwhich:

FIG. 1 illustrates a landing string arrangement which includes featuresaccording to embodiments of aspects of the present invention;

FIG. 2 is a cross-sectional view of a ball valve in accordance with anembodiment of the present invention;

FIG. 3 is a perspective view of a ball member which may be utilised inthe ball valve of FIG. 2, in accordance with an embodiment of thepresent invention;

FIG. 4 is a cross-sectional view of the ball member of FIG. 3 shown incombination with an associated ball seat;

FIG. 5 is an top elevational view of the ball member, ball seat andcoiled tubing shown in FIG. 4;

FIG. 6 is a perspective view of a ball member and ball seat of a ballvalve according to a modified embodiment of the present invention;

FIGS. 7 and 8 are top elevational views of alternative embodiments of aball member according to the present invention;

FIG. 9 is a perspective view of a split outer housing component of avalve according to an embodiment of the present invention, wherein thesplit housing component is shown in a closed configuration and coupledwithin a flowline;

FIG. 10 is a cross-sectional view of a valve assembly which incorporatesthe split outer housing of FIG. 9;

FIG. 11 is a perspective view of a split outer housing component of avalve according to an alternative embodiment of the present invention,wherein the split housing component is shown in an open configuration;and

FIG. 12 is a top elevational view of a ball valve shown located within ariser, in accordance with a modified embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE DRAWINGS

Aspects of the present invention relate to a valve. Such a valve may beused in numerous applications. However, one specific exemplaryapplication will be described below.

A landing string assembly 10 is diagrammatically illustrated in FIG. 1,shown in use within a riser 12 and extending between a surface vessel 14and a subsea wellhead assembly 16 which includes a BOP 18 mounted on awellhead 20. The use and functionality of landing strings are well knownin the art for through-riser deployment of equipment, such as completionarchitecture, well testing equipment, intervention tooling and the likeinto a subsea well from a surface vessel.

When in a deployed configuration the landing string 10 extends throughthe riser 12 and into the BOP 18. While deployed the landing string 10provides many functions, including permitting the safe deployment ofwireline or coiled tubing equipment (not shown) through the landingstring and into the well, providing the necessary primary well controlbarriers and permitting emergency disconnect while isolating both thewell and landing string 10.

Wireline or coiled tubing deployment may be facilitated via a lubricatorvalve 22 which is located proximate the surface vessel 14.

Well control and isolation in the event of an emergency disconnect isprovided by a suite of valves which are located at a lower end of thelanding string 10 inside the BOP 18. The valve suite includes a lowervalve assembly called the subsea test tree (SSTT) 24 which provides asafety barrier to contain well pressure, and also functions to cut anywireline or coiled tubing which extends through the landing string 10.The valve suite also includes an upper valve assembly called theretainer valve 26 which isolates the landing string contents and can beused to vent trapped pressure from between the retainer valve 26 andSSTT 24. A shear sub component 28 extends between the retainer valve 26and SSTT 24 which is capable of being sheared by shear rams 30 of theBOP 18 if required. A slick joint 32 extends below the SSTT 24 whichfacilitates engagement with BOP pipe rams 34.

The landing string 10 may include an interface arrangement forinterfacing with other oil filed equipment. For example, in the presentembodiment the landing string 10 includes a tubing hanger 36 at itslowermost end which engages with a corresponding tubing hanger 38provided in the wellhead 20. When the landing string 10 is fullydeployed and the corresponding tubing hangers 36, 38 are engaged, theweight of the lower string (such as a completion, workover string or thelike which extends into the well and thus not illustrated) becomessupported through the wellhead 20. However, during deployment of thelower string through the riser 12 all the weight and other forcesassociated with the lower string must be entirely supported through thelanding string 10. Furthermore, when deployed a degree of tension isconventionally applied to the landing string 10, for example to preventadverse compressive forces being applied, for example due to the weightof the landing string 10, which can be significant in deep water. Thelanding string 10 must thus be designed to accommodate significantin-service loadings, such as the global tension and bending loads from asupported lower string. Such in-service loadings, which may also includevalve actuation loading, internal and external pressures and the like,must be accommodated across the various valve assemblies, such as theSSTT 24. It is therefore necessary to design the valve housings andappropriate end connections to be capable of accommodating the globalapplied tension, bending loads, valve actuation loading, pressures andthe like.

A cross sectional view of a valve in accordance with an embodiment ofthe present invention is shown in FIG. 2. The valve, which in thecurrent embodiment is a ball valve, may be provided for variousfunctions, but for the purposes of the present description the ballvalve may define a SSTT 24 of the landing string 10 shown in FIG. 1. Itshould be noted that although the SSTT 24 is illustrated in FIG. 1 as adual ball valve, the arrangement shown in FIG. 2 is a single ball valveassembly for purposes of clarity.

The ball valve 24 includes a housing arrangement, generally identifiedby reference numeral 40 which is secured between the upper shear subcomponent 28 and the lower slick joint 32. As such, the ball valve 24 isinstalled in-line with the landing string 10 which can be considered tobe a fluid conduit system. The housing 40 accommodates a valve mechanismwhich comprises a ball seat 42 and a ball member 44, wherein the ballmember 44 is rotatable about axis 46 to selectively close the ball valve24 and control flow through the landing string. In the embodiment shownthe ball member 44 is rotatable in the direction of arrow 48 to closethe ball valve 24. The ball seat 42 and ball member 44 define respectivethrough bores 50, 52 which when aligned define a flow path through thevalve 24 and when misaligned (as shown in FIG. 2) prevent or restrictflow through the valve. When the ball member 44 is closed a sealing area54 is defined between the ball seal 42 and ball member 44.

As will be discussed in further detail below, a leading edge 56 of theball member 44 and/or ball seat 42 is configured to cut through a body(not shown), such as wireline, coiled tubing or the like which extendsthrough the valve 24 and landing string 10 (FIG. 1) upon closure of theball member 44.

As will also be discussed in further detail below, the housingarrangement 40 comprises an outer housing 60 configured to bemechanically secured in-line with the landing string 10 (FIG. 1), and aninner housing 62 located within the outer housing 60 and which isconfigured to contain pressure. The outer housing component 60 comprisesa thin-walled, non-pressure containing cylindrical portion 63 whichextends between axially opposing end flange connectors 64, 66 which areconfigured to be secured to flange components 68, 70 of the shear sub 28and slick joint 32, respectively. In such an arrangement the outerhousing 60 may be defined as a structural housing. That is, the outerhousing 60 may be provided primarily to accommodate mechanical forces,such as axial and bending forces, associated with the landing string 10and any supported lower string while providing minimal or no pressurecontainment, for example of internal and/or external pressures.

The inner housing 62 comprises a generally cylindrical portion or sleeveand does not include any mechanical connection to the landing string 10(FIG. 1). In such an arrangement the inner housing 62 may be defined asa pressure housing. That is, the inner housing 62 may be providedprimarily for pressure containment, for example of internal and/orexternal pressures, while providing minimal or no contribution toaccommodating mechanical loading associated with the landing string 10and/or supported lower string.

This split role arrangement may permit each individual housing 60, 62 tobe designed and/or selected to meet more focussed or specificoperational requirements, providing a number of advantages, such aspermitting a reduction in the global wall thickness of the housing whichcan increase the available internal housing diameter.

The valve mechanism further includes an actuator assembly, generallyidentified by reference numeral 72 for use in actuating the ball member44 to rotate relative to the ball seat 42 between open and closedpositions. In the present example the actuator assembly 72 comprises apiston arrangement.

Various forms of ball member 44 and ball seat 42 may be provided withinthe scope of the present invention. Some exemplary embodiments aredescribed below with reference to FIGS. 3 to 8.

Reference is initially made to FIGS. 3 and 4. FIG. 3 shows a perspectiveview of a ball member, in this case identified by reference numeral 44a, according to an exemplary embodiment of the present invention, andFIG. 4 shown a cross-sectional view of the ball member 44 a of FIG. 3 incombination with an embodiment of a ball seat, in this case identifiedby reference numeral 42 a. Ball member 44 a and seat 42 a have manyfeatures in common with ball member 44 and seat 42 shown in FIG. 2 andas such like features share like reference numerals, suffixed with theletter “a”.

The ball member 44 a defines a through bore 52 a having a bore edge 74,wherein a leading edge 56 a defines a recessed cutting region 76 whichis configured to receive and cut through a body, such as coiled tubing78, shown in broken outline in FIG. 4 extending through the through bore52 a of the ball member 44 a and a through bore 50 a of the ball seat 42a. That is, rotation of the ball member 44 a towards a closed positioncauses the coiled tubing 78 to become engaged between the edge of theball seat 42 a and the recessed cutting region 76 of the ball member 44a, with further rotation effecting cutting of the coiled tubing 78primarily by a shearing action. The ball member 44 a includes a slottedregion 80 which accommodates the lower portion of the coiled tubing 78during rotation of the ball member 44 a.

The recessed cutting region 76 encroaches into the sealing area 54 awhich is defined between the ball member 44 a and ball seat 42 a. Insome embodiments the recessed cutting region may define a relativelyshallow recess such that sealing area 54 a may not be compromised.However, in other embodiments the ability to utilise a thinner walledhousing arrangement 40 by use of separate outer and inner housings 60,62 (having different roles, namely structural and pressure containing)facilitates use of a larger ball member 44 a and ball seat 42 a suchthat even with the presence of the recessed cutting region 76 thesealing area 54 a may be sufficiently large to retain sealing integrity.

In the present embodiment the recessed cutting region 76 is generallyv-shaped. Such a v-shaped cutting region 76 is also shown in FIG. 5(reference to which is also made) which is a top elevation view of theball seat 42 a and ball member 44 a. Such a profile defines two cuttingedges 82, 84 which provide simultaneous initial cutting into separateregions of the tubing 78. In this way, during initial contact two pointsof cutting contact are created which are offset from a central region ofthe tubing 78 and which propagate together as cutting continues. Thisarrangement may permit the force of cutting to be divided between thedifferent points of cutting contact provided by each cutting edge 82,84, assisting to prevent collapsing of the tubing 78 which the presentinventors have discovered can render cutting very difficult. Also, thisarrangement may require less torque through the ball member 44 a to cutthe tubing 78. Such reduced loading is anticipated to reduce damage tothe components of the ball valve which may assist in preventing orreducing any damage to sealing regions, such as sealing area 54 a.

As illustrated most clearly in FIG. 5, in the present embodiment, theleading edge 86 of the ball seat 42 a does not include any recessedregion. However, in other embodiments, the ball seat may also (oralternatively) include a recessed region. Such an embodiment isillustrated in FIG. 6 which is a perspective view, from below, of a ballseat 42 b and ball member 44 b which both include recessed cuttingregions 88, 90.

In the exemplary embodiments described above the recessed cutting regionis generally v-shaped. However, other arrangements are possible. Forexample, a ball member 44 c (or a corresponding ball seat) may include agenerally arcuate recessed region 92 as shown in FIG. 7. Furthermore, inthe exemplary embodiments described above a single recessed cuttingregion is provided. However, in other arrangements multiple recessedregions may be provided. For example, a ball member 44 c (orcorresponding ball seat) may include a pair of (or more) recessedregions 94 as shown in FIG. 8. In such an embodiment a projection 96 maybe defined between each recessed region 94 which may function to piercea body, such as coiled tubing, to assist in initiating cutting whileminimising adverse collapse or the like. Such a projection may beprovided within embodiments including a single recess.

A perspective view of the ball valve 24 illustrated in FIG. 2 is shownin FIG. 9, reference to which is now made, along with FIG. 10 whichshows a further cross-sectional view of the ball valve 24 with the ballmember 44 and actuator 72 removed for clarity.

As described above, the housing arrangement 40 of the valve 24 includesan outer housing 60 and a separate inner housing 62, wherein the outerhousing 60 includes opposing flange connectors 64, 66 which are securedto the respective flange components 68, 70 of the shear sub 28 and slickjoint 32. Each flange connection 64, 68 and 66, 70 is made via aplurality of bolts 100, wherein one or more of the bolts 100 may bepre-tensioned to provide a degree of preloading through the connections.

The inner housing 62 is axially retained between the flange connectors64, 66 of the outer housing 60. Furthermore, the ball seat 42 isinterposed between the upper flange connector 64 and the upper end ofthe inner housing 62.

The inner housing 62 defines a unitary cylindrical component, whereasthe outer housing 60 is longitudinally split along a line of separation102 such that the outer housing 60 is formed from two half segments 104,106. Referring also to FIG. 11, this split arrangement permits the outerhousing 60 to be opened to provide access to install, inspect, repair,replace or the like the inner housing 62 and other components, such asthe ball seat 42. Splitting a housing of a valve is generally notattempted in the art. However, the present invention permits the outerhousing 60 to be split as this does not need to provide any sealing orpressure retaining function, which instead is provided by the unitaryinner housing 62.

The segments 104, 106 are hinged together along one side 108 and onceclosed may be retained closed upon connection of the respective flangeconnectors 64, 66 to the flange components 68, 70 of the shear sub 28and slick joint 32. Additionally, a longitudinal connecting arrangement110 is provided which longitudinally secures the segments 104, 106together when closed. In an alternative embodiment no hinge connectionmay be provided and instead both sides may be bolted to secure togetherthe different segments 104, 106. Providing such a longitudinalconnection arrangement 110 establishes appropriate hoop stiffness withinthe outer housing 60 which may be required to resist bending forces, forexample.

The longitudinal connection arrangement 110 may be provided in a numberof forms. In this respect one such form is illustrated in FIG. 9(identified by reference numeral 110 a), whereas an alternative form isillustrated in FIG. 11 (identified by reference numeral 110 b).

The longitudinal connection arrangement 110 a of FIG. 9 comprises aplurality of tangential-type bolts or cap screws 112 which extendthrough respective flange fingers or ribs 114 on one housing segment 106and engage threaded holes (not illustrated) in the opposing housingsegment 104. Each adjacent flange finger or rib 114 is separated by aslotted region 116. This geometry assist to redirect stress along thisregion of connection to, for example, prevent high stresses at thelocations of the cap screws 112 during tensile loading.

The longitudinal connection arrangement 110 b illustrated in FIG. 11comprises a plurality of interleaving components 118 on each segmentwhich are interleaved with each other when the segment halves 104, 106are closed. Each interleaving component 118 comprises an axiallyextending bore 120 which become aligned when the segment halves 104, 106are closed. An elongate connecting member 122 is provided which isreceived within the aligned bores 120 to thus secure the segment halves104, 106 together.

In the embodiments described above, such as with reference to FIGS. 2and 9 to 11, the outer housing defines a generally cylindrical outerprofile. However, in other embodiments a non-cylindrical outer profilemay be provided, as illustrated in FIG. 12. In this embodiment a valve,generally identified by reference numeral 124, includes a split outerhousing 160 and a unitary inner housing 162, in a similar manner to theembodiments described above for similar reasons. However, in the presentembodiment the outer housing 160 defines a generally oval outer profile.This arrangement permits other components, such as the illustratedumbilical 123 to be accommodated between the valve 24 and an outerconstraining component, such as a riser 12.

It should be understood that the embodiments described herein are merelyexemplary and that various modifications may be made thereto withoutdeparting form the scope of the present invention. For example, thedisclosed valve embodiments are not solely for use within a landingstring, and may be used in many other applications as would beunderstood by a person of skill in the art. Furthermore, the multiplecomponent housing arrangement may also be used in combination withdifferent valve types, and is not limited solely for use in ball valeapplications.

1. A valve comprising a valve mechanism located within a housingarrangement, wherein the housing arrangement comprises an outer housingconfigured to be mechanically secured with a fluid conduit system, andan inner housing located within the outer housing and configured tocontain pressure.
 2. The valve according to claim 1, wherein the outerhousing is securable in-line with a fluid conduit system.
 3. The valveaccording to claim 1, defining or forming part of at least one of aSubsea Test Tree (SSTT), a retainer valve and a lubricator valve.
 4. Thevalve according to claim 1, wherein the outer housing comprises aconnection arrangement for permitting mechanical connection with a fluidconduit system.
 5. The valve according to claim 4, wherein theconnection arrangement comprises first and second connectors forsecuring with a fluid conduit system.
 6. The valve according to claim 5,wherein at least one of the first and second connectors comprises aflange connector.
 7. The valve according to claim 5, wherein at leastone of the first and second connectors defines a preloaded connector. 8.The valve according to claim 1, wherein the inner housing is axiallycontained within the outer housing.
 9. The valve according to claim 8,wherein the outer housing comprises a connection arrangement comprisingfirst and second connectors for securing with a fluid conduit system,wherein the inner housing is axially contained between the first andsecond connectors of the outer housing.
 10. The valve according to claim1, wherein at least a portion of the valve mechanism is axially locatedbetween the outer and inner housings.
 11. The valve according to claim1, wherein the outer housing comprises an axially extending wall sectionto encapsulate the inner housing.
 12. The valve according to claim 1,wherein the outer housing is split.
 13. The valve according to claim 1,wherein the outer housing is longitudinally split.
 14. The valveaccording to claim 1, wherein the outer housing comprises at least twohousing segments.
 15. The valve according to claim 14, wherein thehousing segments are hingedly connected together.
 16. The valveaccording to claim 14, wherein the housing segments are secured togetherwhen the outer housing is secured to a fluid conduit system.
 17. Thevalve according to claim 14, wherein the housing segments are securedalong a length of separation defined between the different housingsegments.
 18. The valve according to claim 14, wherein the housingsegments are secured together by a bolting arrangement.
 19. The valveaccording to claim 18, wherein the bolting arrangement is provided alongone or more sides or regions of separation between different housingsegments.
 20. The valve according to claim 14, wherein the housingsegments are secured together via one or more tangential bolts.
 21. Thevalve according to claim 14, wherein adjacent housing segments compriseone or more connecting portions extending at least partially along thelength of split defined between the adjacent housing segments, whereinopposing connecting portions of each segment are arranged to be securedtogether.
 22. The valve according to claim 21, wherein a plurality ofconnecting portions are provided on each adjacent housing segment. 23.The valve according to claim 22, wherein axially adjacent connectingportions on a single housing segment are separated by a slotted region.24. The valve according to claim 1, wherein at least a portion of theouter housing defines a generally cylindrical outer profile.
 25. Thevalve according to claim 1, wherein at least a portion of the outerhousing defines a non-cylindrical outer profile having differentdimensions in mutually perpendicular lateral directions.
 26. The valveaccording to claim 1, wherein the inner housing is isolated frommechanical connection with a fluid conduit system.
 27. The valveaccording to claim 1, wherein the inner housing is defined by a pressurecontaining sleeve.
 28. The valve according to claim 1, wherein at leasta portion of the valve mechanism defines part of the inner housing. 29.The valve according to claim 1, wherein the valve mechanism comprises aball valve mechanism.
 30. The valve according to claim 1, wherein thevalve mechanism is operable to cut a body extending at least partiallythrough the valve.
 31. The valve according to claim 1, wherein the valvemechanism is operable to cut an elongate body including at least one oftubing, coiled tubing, wireline, slickline and a tool string.
 32. Thevalve according to claim 1, wherein the valve mechanism comprises a ballvalve mechanism which includes a ball seat and a ball member, whereinthe ball member is rotatable relative to the ball seat to provide flowcontrol.
 33. The valve according to claim 32, wherein the ball seat andball member define respective through bores each having a bore edge andthe bore edge of at least one of the ball seat and ball member isconfigured to cut a body extending at least partially through the valveupon closure of the ball member.
 34. The valve according to claim 33,wherein the bore edge of at least one of the ball seat and ball memberdefines a recessed cutting region for cutting a body.
 35. A method forcontrolling flow along a fluid conduit system, comprising: securing avalve housing arrangement to a fluid conduit system, wherein the valvehousing arrangement includes an outer housing which provides mechanicalconnection to the fluid conduit system and an inner housing locatedwithin the outer housing and which contains pressure; and controllingflow along the fluid conduit using a valve mechanism located within thevalve housing.
 36. A sub sea test tree comprising: a housingarrangement; and a valve mechanism located within a housing arrangement,wherein the housing arrangement comprises an outer housing configured tobe mechanically secured with a fluid conduit system, and an innerhousing located within the outer housing and configured to containpressure.